A few kinds of coffee processes remove the cherry by allowing it to ferment, which can create alcoholic/boozy flavors in coffee. I don't speak German but I did a bit of a deep dive on honey processes in Costa Rica and apparently "black diamond" honey process takes 22 days or more to ferment the cherries slowly (this roaster is probably sourcing from the same or a nearby farm). Also, having the warm water sit in the grounds probably accentuates the fermented/funky/wine-like smells. Next time you taste that coffee, try and see if there is any whiskey flavors or smells.
Side note: whiskey/fermented grain mash is a recognized coffee flavor note in the World Coffee Research Sensory Lexicon as well as smoky flavors you might expect in a bourbon.
It is also common to age coffee in bourbon barrels as others have mentioned.
What even is seasoning a grinder? My assumption is just that you're filling up micro pores in the metal with fines.
You could probably just grind about 10g of coffee beans almost as fine as possible. It shouldn't take much. If you don't want to waste it, use the results in a baking dish like chocolate chip cookies or brownies. It can add some richness to counteract the sugar.
A home grinder isn't going to be that fussy.
I also think that just beginning to use it normally is fine too. The only reason not to would be the idea that an unseasoned grinder somehow ruins the resulting first coffee, which is clearly not true. And seasoning with shit coffee is just gonna make your coffee taste a little bit shittier.